6537991 has 2 divisors, whose sum is σ = 6537992. Its totient is φ = 6537990.

The previous prime is 6537989. The next prime is 6538001. The reversal of 6537991 is 1997356.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6537991 - 2¹ = 6537989 is a prime.

Together with 6537989, it forms a pair of twin primes.

It is a zygodrome in base 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6537941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3268995 + 3268996.

It is an arithmetic number, because the mean of its divisors is an integer number (3268996).

Almost surely, 2^6537991 is an apocalyptic number.

6537991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6537991 is an equidigital number, since it uses as much as digits as its factorization.

6537991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51030, while the sum is 40.

The square root of 6537991 is about 2556.9495497565. The cubic root of 6537991 is about 186.9884461963.

The spelling of 6537991 in words is "six million, five hundred thirty-seven thousand, nine hundred ninety-one".